ALEXANDRIA, Va. — Alexandria police announced Thursday that the bullets that killed Ruthanne Lodato in February are similar to bullets that killed two other prominent Alexandrians, one of them 10 years ago.

All three killings — Ruthanne Lodato, 59, Ronald Kirby, 69, and Nancy Niedermeier Dunning, 56 — occurred in the same general area of Alexandria, in the middle of the day, and are so far unsolved. This is the first time that authorities have said that the three high-profile cases could be linked.

While they cannot say what kind of gun the bullet fragments came from, police say they all came from a small-caliber gun.

“We’re looking at their histories, their victimization and the other similarities between these three homicides,” said Alexandria Police Chief Earl Cook.

Lodato, a former school teacher and active member of her church, was shot on Feb. 6 as she answered the door to her home at the 2400 block of Ridge Road Drive. A caregiver at the home was also shot, but survived the attack.

Lodato’s killing is the only one of the three cases that generated a description of the shooter: an older man with graying hair and beard, wearing a dark coat.

While police do not have a sketch for the Dunning and Kirby killings, they are asking residents in the area to take a look at the Lodato homicide sketch and consider again if they had seen this man around the neighborhood at the time of the shootings.